笔记 j2se 数据类型转换

  1. Integer转换成int的方法

    Integer i = new Integer(10);
    int k = i.intValue();
    即Integer.intValue();

  2. int转换成Integer

    int i = 10;

    Integer it = new Integer(i);

  1. String转换成int的方法

    String str = “10”;
    Integer it = new Interger(str);

    int i = it.intValue();

    即:int i = Integer.intValue(string);

  1. int转换成String

    int i = 10;

  • String s = String.valueOf(i);
  • String s = Ingeger.toString(i);
  • String s = “” + i;
  1. String转换成Integer

    String str = “10”;

    Integer it = Integer.valueOf(str);

  1. Integer转换成String

    Integer it = new Integer(10);

    String str = it.toString();

  1. String转换成BigDecimal

    BigDecimal bd = new BigDecimal(str);

  1. 日期

    Calendar calendar = Calendar.getInstance();
    int year = calendar.get(Calendar.YEAR);
    int month = calendar.get(Calendar.MONTH)+1;
    int day = calendar.get(Calendar.DATE);

    //获取今天的日期字符串
    String today = java.text.DateFormat.getDateInstance().format(new java.util.Date());
    //获取今天的日期
    new java.sql.Date(System.currentTimeMillis());